A stationary extrusion press is described in DE 23 03 109 A, that is arranged for pressing of cereal crop into briquettes. The extrusion press is equipped with a moisture measuring arrangement that encloses an extrusion guide containing the extrusion produced that can detect the moisture contents by means not described in any further detail, for example, by measurement of the dielectric constant. Accordingly, the measurement of the moisture content is performed downstream of the press itself.
A mobile baler is proposed by DE 32 32 746 A with a moisture measuring arrangement. The latter contains moisture measurement electrodes attached to hold-downs. The hold-downs are located above a take-up drum and are pressed against the harvested crop by springs.
EP 1 029 440 A describes an agricultural large round baler with a moisture measuring arrangement not specified in any further detail that is located on the underside of a bale produced in the baling chamber.
DE 102 04 941 A, that is regarded as forming the class, proposes a movile large round baler with a capacitor type sensor arranged on a side wall of the baling chamber for the detection of the moisture content of the bale.
As a rule, such mobile balers are equipped with moisture sensors for purposes of mapping the yield or for the control of the automatic dispensing of preservatives. The attachment of the sensors has been found to be problematical. The arrangement according to DE 32 32 746 A has the disadvantage that the harvested crop just taken up is examined before baling, this crop still being relatively loose. The result of the measurement is affected largely by the air between the stalks of the harvested crop and is therefore not representative of the actual crop. The moisture sensors according to EP 1 029 440 A and DE 102 04 941 A in each case interact with only relatively small areas of the bale. The small measurement areas result in locally varying crop moisture values and varying mechanical characteristics of the harvested crop that results in varying distances between the harvested crop and the sensors and hence sharply varying measurement values that are subject to large errors. Therefore, the known sensors have shown not to be useful in actual applications.
The problem to be solved then is that of providing a baler with a moisture sensing arrangement which results in obtaining moisture information which is accurate relative to substantially all of the crop contained in a bale.